1. Field of the Invention
The present invention relates to a bearing for a motor and, more particularly, to a bearing including at least one guiding groove defined in a peripheral wall defining an axial hole of the bearing and extending axially into an end face of the bearing for enhancing the lubricating effect.
2. Description of Related Art
FIGS. 1 and 2 show a conventional oily bearing for a motor. The oily bearing 8 includes a central hole 81 extending longitudinally through a central portion thereof for receiving a shaft 9. A plurality of extension grooves 82 are defined in a peripheral wall defining the central hole 81 and located outside the shaft 9 and extends longitudinally from a top face through a bottom face of the oily bearing 8. An example of such an oily bearing is disclosed in Taiwan Patent Publication No. 542317. The extension grooves 82 reduce the friction between the shaft 9 and the oily bearing 8 by reducing the contact area therebetween, thereby lowering the temperature resulting from friction while increasing the amount of lubricant received in the oily bearing 8 to prolong the life of the motor.
However, since bottoms of the extension grooves 82 are in communication with the bottom of the central hole 81 of the oily bearing 8, the lubricant received in the extension grooves 82 is liable to escape during rotation of the rotor 9 and, thus, adversely affects the lubricating effect. Ambient impurities such as dust or particles are liable to enter the gap between the oily bearing 8 and the shaft 9, and the lubricant in the oily bearing 8 is apt to oxidize and turn into carbide at high temperature. The carbide and the impurities increase the friction between the oily bearing 8 and the shaft 9 and, thus, shorten the life of the motor.